Lecture 5: Microparasites II - Persistence and Impacts

In addition to host births and seasonality in contact rates, what other factors promote parasite persistence?

migration, immigration of hosts from another region, loss of immunity, pathogen evolution (to overcome immunity), re-introduction from another species

How do pathogens affect host populations?

cause population declines, reduce net population growth rate, regulate populations

what does virulence in the denominator mean?

a more virulent parasite should be less likely to invade a host population

if parasites affect host survival, those of intermediate virulence will …

depress the population size the most

SIR models can be modified by…

adding host births, deaths, or virulence

persistence mechanisms include…

host births, loss of immunity, or reintroduction

virulent parasites can regulate host populations by …

adding extra mortality for infected hosts